This invention relates to matrix composites and processes for making them.
A fiber-reinforced composite, or matrix composite, is an article comprising a plurality of fibers (the reinforcement) embedded in a plastic (the matrix). Typically, the fibers give strength and/or stiffness to the composite, and the matrix maintains fiber alignment and transfers load around broken fibers. Matrix composites are described in detail in numerous references, such as Kirk-Othmer Ency. Chem., Tech.-Supp., Composites, High Performance, at 260-281 (J. Wiley & Sons 1984)
A number of fibers are available for use in matrix composites, each having different combinations of tensile and compressive strength and modulus, temperature stability, creep, cost, and other properties. Suitable fibers may contain, for example, aramid (such as Kevlar.TM. fibers), boron, glass, carbon, gel-spun polyethylenes (such as Spectra.TM. fiber), polybenzoxazole, polybenzothiazole, or polybenzimidazole. Suitable fibers and processes for their fabrication are described in numerous references, such as U.S. Pat. No. 4,533,693; 3 Kirk-Othmer Ency. Chem. Tech., Aramid Fibers, 213 (J. Wiley & Sons 1978); Kirk-Othmer Ency. Chem., Tech.-Supp., Composites, High Performance, at 261-263; 11 Ency. Poly. Sci. & Eng., Polybenzothiazoles and Polybenzoxazoles, 601 (J. Wiley & Sons 1988) and W. W. Adams et al., The Materials Science and Engineering of Rigid-Rod Polymers, at 245-312 (Materials Research Society 1989).
A number of matrix materials are also available for use in matrix composites. Examples of polymer matrix materials include polyesters, epoxy resins, polycyanates, polybutadienes, vinyl ester resins and polyimides. Some carbon matrix composites have been made. Metal and ceramic matrix composites are also known.
There is a need for improved matrix materials in advanced matrix composites. For example, the nonflammability, chemical resistance, solvent resistance and thermal stability of many polymer matrix materials is much poorer than the same properties of the fiber reinforcement. Stronger polymer matrices could yield stronger composites using the same amount of fiber. Metal matrix materials are heavier than polymers. Ceramic and carbon matrix materials are expensive and brittle. An objective of the present invention is to provide a fiber-reinforced composite having new polymer matrix materials.